The present invention generally relates to a process unit used in an electrophotography imaging apparatus such as a laser beam printer, a copy machine, or a facsimile set, and more particularly to a process unit having a developing device and a storage box which stores waste developer fed from a cleaning device.
In a general electrophotography imaging apparatus such as a laser printer, a developing device develops a latent image which is optically formed on a image retaining member (e.g. a photosensitive drum) That is, toner (developer) is adhered to the latent image formed on the image retaining member. Then this toner image is transferred from the image retaining member to a recording sheet and fixed thereon by a fusing unit. Most of the toner forming the image can be transferred to the recording sheet, but a small amount of the toner remains on the surface of the image retaining member. A cleaning unit cleans the residual toner from the image retaining member so that a new latent image can be formed on the image retaining member. The residual toner removed from the surface of the image retaining member is, as waste toner, stored in a storage box. Conventionally, the storage box is placed adjacent to the cleaning unit, and the residual toner is fed from the cleaning unit to the storage box, for example, as disclosed in Japanese Laid Open Patent No. 60-230178.
On the other hand, a process unit including the developing device which is detachably mounted in a main assembly of the electrophotography imaging apparatus has been proposed. In this electrophotography imaging apparatus, if the storage box in which the waste toner is stored is mounted in the process unit, the waste toner can be removed from the electrophotography imaging apparatus when the process unit is exchanged for a new one.
In a case where the storage box in which the waste toner is stored is mounted in the process unit, there is a disadvantage in that the process unit becomes large.